bbb bbe bbk bbo bbs bbt bbx be- beb bee bek beo bes bet bex bkb bke bkk bko bks bkt bkx bob boe bok boo bos bot box bsb bse bsk bso bss bst bsx btb bte btk bto bts btt btx bxb bxo bxx ebb ebe ebk ebo ebs ebt ebx eeb eee eek eeo ees eet eex ekb eke eko eks ekt eo- eob eoe eok eoo eos eot es- esb ese esk eso ess est esx etb ete etk eto ets ett etx ex- exe exo exs ext exx k-t kbb kbe kbk kbo kbs kbx ke- keb kee kek keo kes ket kex kkb kke kkk kks kkt kob koe kok koo kos kot ksb kse ksk kso kss kst ktb kte ktk kto kts ktt kxo ob- obb obe obk obo obs obt obx oeb oee oeo oes oet oex okb oke okk oko oks oo- oob ook ooo oos oot oox os- osb ose osk oso oss ost osx ot- otb ote otk oto ots ott ox- oxb oxo oxt oxx sbb sbe sbk sbo sbs sbt sbx se- seb see sek seo ses set sex sk- skb ske skk sko sks skt skx sob soe sok soo sos sot sox ss- ssb sse ssk sso sss sst ssx stb ste stk sto sts stt stx sxs sxt t-x tbb tbe tbk tbo tbs tbt te- teb tee tek teo tes tet tex tkb tke tkk tko tks tkt to- tob toe tok too tos tot tox tsb tse tsk tso tss tst tsx ttb tte ttk tto tts ttt ttx txe txk txs txt xbe xbx xee xes xet xex xkb xke xks xok xoo xos xot xox xsb xss xst xts xtx xxo xxx